User 1 is hosted by Virtual World (VW) A. User 1 has user 2 on his friends list. User 1 looks at his friends list and sees that user 2 is offline. User 1 interacts with his friends list such that it alerts him when user 2 comes online. Later, user 1 is alerted that user 2 is online (potentially hosted by VW B, on a mobile phone, or on a chat engine). User 1 initiates an IM exchange with user 2.
I'm in Virtual World A and want to send a text message to Totally Virtual, who is not in the World, but is available either on computer via IM or on cell via SMS. I want my message to be routed to his current active message service. (Ability to send IMs between IM (computer), SMS (phone) and virtual world.)
This depends on Use Case: Presence and Use Case: Friend List. This is the text equivalent of Use Case: Call in/out.
Standard: data format for message interchange; routing and service identification